Recent storms , snowpack results lead to higher water allocations for farms and cities
On Tuesday, the Department of Water Resources (DWR) announced that recent storms have allowed for another increase to the State Water Project (SWP) allocation forecast for 2025. The allocation has increased to 35 percent of requested water supplies, up from 20 percent in January based on increases in precipitation, snowpack, and reservoir storage. The SWP provides water to 29 public water agencies that serve 27 million Californians and 750,000 acres of farmland across the state.
The latest allocation forecast takes into account precipitation and snowpack conditions up to Feb. 10, prior to a cold storm that brought welcome snow to the Sierra. That snowpack is included in future water supply calculations along with any forecasted dry conditions ahead.
“California is experiencing a winter of extremes. We’ve seen predominately dry conditions broken up by very wet, short storm events. Those conditions mean we must move as much water when it’s available and as safely as possible,” said Karla Nemeth, director of the Department of Water Resources. “Ultimately it will require new infrastructure to move and store enough water for California as dry spells last longer and wet periods become shorter and flashier.”
Projects like the proposed Sites Reservoir and Delta Conveyance Project would have been hugely beneficial if they were in place this season, allowing California to capture more water for use during the dry summer months. For example, the Delta Conveyance Project could have captured more than 700,000 acre-feet of additional storage so far this winter, which is enough to support more than 7 million people and nearly 2.5 million households. That also would have translated to approximately a 15 to 20 percent increase in the current State Water Project allocation, on top of the increase announced today.
Managing the existing system to capture as much stormwater as possible, water managers made required flood control releases from Lake Oroville in February and still were able to add 300,000 acre-feet of storage to the reservoir, bringing it up to 84 percent capacity.
Also this month, water managers took advantage of increased flexibility in new operating permits for the State Water Project to move approximately 16,000 acre-feet of additional water into San Luis Reservoir, which is now at 81 percent capacity. The pumping increase was made possible in part by the “storm flex” provisions in the State Water Project’s 2024 federal and state endangered species act permits, which allow for additional diversion of water supply when certain ecological conditions are met during storms. The action aligned with Gov. Gavin Newsom’s Jan. 31 direction to DWR to maximize diversion of excess storm flows to boost the state’s water storage.
Each year, DWR provides SWP allocation forecasts based on available water storage, projected water supply, and water demands. Allocations are updated monthly as snowpack, rainfall, and runoff information is assessed, with a final allocation typically determined in May or June. Learn more about how the State Water Project allocation process works at https://water.ca.gov.
The allocation forecast notice to State Water Contractors and historical data on SWP allocations are available at https://https://water.ca.gov/programs/state-water-project/management/swp-water-contractors.
